The invention relates to piston machines having arcuately curved pistons and cooperating cylinders each rotating circumferentially in a circular path on separate, relatively swingable supporting parts carried about a machine shaft fixed in a housing and working with a compressible fluid. Combustion engines are known having pistons rotating in an annular or ring cylinder and having lagging counter-pistons to control fluid compression. Control of piston movements in such engines occurs through levers and gears. Forces imposed by explosions in the cylinders of combustion engine embodiments have not been satisfactorily controlled, so such motors have never been produced in volume. Other combustion engines have been proposed having constantly rotating cylinders and stepwise rotating pistons moving in a circular path and controlled by a lever system. Such motors also have control and sealing problems. Such machines also have had drives which could inadvertently lock or levers which could depart from their control paths.
In view of the state of the art, an object of the invention is to provide a piston machine successfully utilizing the advantages of rotational movement of pistons and cylinders.